122 MOSSES AND LIVEEWOETS 



different species, in some cases growing close 

 to the fruit-bearing organs, while in others 

 separated from them. Thus, in the frondose 

 liverworts they are often found imbedded in the 

 substance of the frond, their presence being not 

 unfrequently indicated in the microscope by a 

 number of dark, circular markings on the upper 

 face of the frond, which are in fact caused by the 

 small depressions in which they lie, and which 

 are covered over by the delicate skin of the 

 frond. On the other hand, in the well-known 

 Common Liverwort (Marchantia polymorpha) a 

 plant which grows plentifully in damp and wet 

 situations, for instance on the sides of a well or 

 spring in the wall by the roadside, or the shady 

 corners of a greenhouse, literally covering the 

 rock or earth with its flat green fronds the 

 reproductive organs are housed in small round 

 discs or receptacles, each at the end of a long 

 stalk, the whole bearing a strong resemblance to 

 a tiny parasol. When produced in considerable 

 numbers, as is frequently the case, the numerous 

 pale green heads springing up from the flat, 

 shining green undergrowth, make a very pretty 

 sight. In the leafy liverworts the fertilising 

 organs frequently arise in the axils of the leaves, 

 and we may sometimes get a glimpse of them in 

 the microscope through their beautiful leafy cover- 

 ings, as is shown in Plate IX. fig. 2, which 

 represents a small piece of the Eound-fruited 



